Folding apparatus

ABSTRACT

A continuous web assembly, having uniformly spaced transversely extending lines of cross perforation, is fed downwardly by an endless pin belt through an oscillating guide chute which initiates the folding of the web in a zig-zag manner. Folding spirals are mounted on the upper end portions of vertical stub drive shafts, and a series of semi-circular beaters are mounted on horizontal shafts for rotation between the spirals. Elongated flexible arms on the leading edges of the spirals resiliently engage the inner part of the folding web behind the cross perforations and near the web edges, to pull the web from the chute and to promote a clean fold while guiding the web onto the spirals. The positions of the brushes and spirals are independently adjustable on the drive shafts for varying their individual phases with respect to the remainder of the apparatus.

Al n M .3 S .w a the S Stephens ABSTRACT FOLDING APPARATUS Inventor: Frank Douglas Stephens, Arcanum,

Ohio A continuous web assembly, having uniformly spaced transversely extending lines of cross perforation, is fed [73] Asslgnee' 2 i g g Corporation downwardly by an endless pin belt through an oscillateve ing guide chute which initiates the folding of the web Sept. 26, 1973 in a zig-zag manner. Folding spirals are mounted on the upper end portions of vertical stub drive shafts, and a series of semi-circular heaters are mounted on horizontal shafts for rotation between the spirals.

22 Filed:

Appl. No.: 401,039

[52] US. 270/79 Elongated flexible arms on the leading edges of the [51] Int. spirals resiliently engage the inner part of the folding web behind the cross perforations and near the web [58] Field of Search........... 270/79, 61 F, 73, 39, 4O

edges, to pull the web from the chute and to promote [56] Reference Cited a clean fold while guiding the web onto the spirals.

UNITED STATES PATENTS The positions of the brushes and spirals are indepen- 27O/39 dently adjustable on the drive shafts for varying their 270/79 individual phases with respect to the remainder of the apparatus.

1,348,846 8/1920 Brown..... 3,124,350 3/1964 Primary Examiner-Melvin D. Rein Assistant ExaminerA. Heinz 9 Claims, 13 Drawing Figures Attorney, Agent, or FirmBiebel, French & Bugg US. Pamnt 0t.14,1975 SheetlofZ 3,912,252

U... atent Oct.14,1975 Sheet20f2 3,912,252

FIG-4 FOLDING APPARATUS BACKGROUND OF THE INVENTION Multiple copy business forms are usually produced by collating a plurality of printed webs in registration and then securing the webs together with longitudinally spaced lines or spots of glue and/or a series of crimps. The assembled webs commonly have longitudinally spaced lines of cross perforation where the web assembly is zig-zag folded by a folding apparatus, immediately after the webs are assembled. Examples of devices for performing the latter function include US. Pat. Nos. 1,436,302, 1,625,566 and 2,077,878.

The folding apparatus preferably includes an oscillating chute through which the web assembly is fed into a set of rotating folding screws or spirals. The spirals are mounted on vertical drive shafts located below the oscillating chute for receiving the edges of the webs adjacent the lines of cross perforation as the web issues from the chute. The spirals and their drive shafts are adjustable in pairs for accommodating webs of different widths and folds of different lengths.

The folding apparatus also commonly includes sets of semi-circular beaters which are mounted on laterally extending horizontal shafts between the folding spirals, and which are rotated in timed relation with the rotation of the folding spirals to assure that the web is properly creased at the fold lines. The horizontal shafts supporting the beaters are located in back of or outwardly of the vertical shafts which support the folding spirals, and the oscillating guide chute is adjustable in length to assure adequate clearance between it and the spirals.

However, such an arrangement does not always maintain a continuous feed of the forms through the chute, nor does it always initiate a proper fold along the perforation lines. For example, proper feed of the paper is maintained when the chute is in the midpoint of its swing from one extreme to the other, since the paper forms are held by the spirals behind the chute and are pulled out of the chute as it swings away from the spirals. However, since the chute must oscillate back and forth, each change in direction requires the chute to decelerate, stop, and accelerate in the opposite direction. As the chute reaches an extreme and reverses its travel, the paper thus goes slack since there is nothing pulling it from the chute at that point.

As a result, the multiple forms back up in the chute at each extreme of its travel. The problem is only partially remedied by ramming the paper into the chute with endless pin belts, since this is somewhat like trying to push a rope. Further, while the chute is reversing its travel, the paper which continues to leave the chute forms a loop or bubble" due to the extra slack now provided in the web. If multi-layered webs are loose (not glued) along one side edge, or if stiff glue lines are used to join the webs, the bubble can be very difficult to handle. Particularly for long fold lengths, there is then a tendency to lose control of the slack web, and this problem is aggrevated during the next return swing of the chute since both single and multi-ply webs are snapped by the sudden restoration of tension, sometimes breaking the cross perforations or causing a faulty fold.

Another problem concerns the corners of the fold at each cross perforation line. Occasionally these corners are formed improperly when the innermost layer backfolds, since there is little to guide the web edges for proper folding at the time the perforation line is creased.

SUMMARY OF THE INVENTION The present invention is directed to a spiral folding apparatus of the type generally described above, and incorporating an improved mechanism for feeding, creasing, and folding the web, and for guiding the web onto the folding spirals. The improved folding mechanism provides for safer, higher speed operation, and is particularly adapted for folding assembled webs which are difficult to fold due to the type of webs, the number of webs, and/or the glue lines used for securing adjacent webs together.

In accordance with one embodiment of the invention, the assembled webs are fed downwardly by an endless pin belt into a guide chute having low friction internal plastic guides for the web. The chute oscillates back and forth between two sets of folding heads, each of which includes a folding spiral and one or more corresponding beater members. One set of folding heads is adjustable relative to the other set for accommodating folds of different lengths, and one folding head of each set is adjustable relative to the other of the same set for accommodating webs of various widths.

In each folding head, the folding spiral is drivably mounted on the upper end portion of a vertical stub drive shaft which is driven by a main drive. The beater members are supported by horizontal shafts passing between respective pairs of heads and driven at a speed correlated with the speed of the folding spiral and the oscillating frequency of the guide chute. The folding spiral makes two revolutions for each revolution of the beater and each oscillation of the guide chute.

The stub shafts for driving the spirals are toothed on the outside and the spirals have matching teeth on the inside, so that the positions of the spirals on their respective drive shafts may be adjusted simply by lifting the spiral off its shaft and turning it until the desired position is reached. A large number of teeth allows the adjustment to be very precise.

Elongated flexible arm members, such as brushes or spiral springs, are mounted adjacent the leading edges of the spirals and extend radially therefrom. The arm members, or brushes, are mounted in collars which are toothed on the inside for reception onto the ends of the spiral drive shafts above the spirals. The positions of the collars and brushes on their drive shafts are thus also easily and independently adjustable on their drive shafts, so that the relative phases of each of the spirals and each of the brushes may be easily and quickly adjusted, as desired, with respect to the remainder of the folding machine. A manually operable thumb screw is threaded into the end of the drive shaft to hold the brush collar and the spiral thereon.

The brushes engage the web resiliently behind the cross perforations near the web edges to maintain tension on the web and to continue pulling it out of the chute. The web is thus delivered from the chute continuously and does not back up and then snap on the next return swing of the chute.

The brushes also assure proper creasing of the web and promote clean and rapid folding of the web on the perforations. They engage the web behind each perforation line and push the inside of the line outwardly along eachcorner, keeping loose web layers together and helping to break stiff glue lines to form a clean,

sharp crease. As the arms and spirals then continue rotating, the arms flex and yield backwardly within the web fold, toward the spiral periphery. This promotes a clean fold while preventing tearing of the web as the arm is forced from behind the fold by the continued spiral rotation.

It is therefore an object of the present invention to provide a resilient arm member for a spiral brush folder for improving the operation of a folding machine for cross-perforated webs; a member which maintains substantially uniform and continuous feed of the web into the folding spirals of the machine; which assists in the proper folding of, and crease formation on, the webs;

I which is easily adjustable on a web folding machine for the desired and proper phase with respect thereto; and to accomplish the above objects and purposes in an inexpensive and durable configuration readily and easily adaptable to existing web folding machines.

Other features and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 a somewhat diagrammatic side view of a folding apparatus incorporating the improved spiral brush folder of the present invention;

FIG. 2 is a partial cross-sectional side view of one of the folding head assemblies, taken on line 2-2 in FIG.

FIG. 3 is a somewhat diagrammatic top view of the FIG. 1 apparatus;

FIG. 4 is a cross-sectional view of the FIG. 2 head assembly taken generally one line 4-4 in FIG. 2;

FIG. 5 is a top view of one of the spiral brush assemblies of the present invention;

FIG. 6 is a side view of the FIG. 5 assembly;

FIG. 7 is an exploded side view, partially in section, of the assembly of FIGS. 5 and 6;

FIGS. 8A-8C are diagrammatic top view illustrations of the brush, spiral, and web during successive stages of the formation of a web fold, with FIG. 8A taken generally on line 8A8A in FIG. 9A; and

FIGS. 9A-9C are diagrammatic side views corresponding to FIGS. 8A-8C.

DESCRIPTION OF THE PREFERRED EMBODIMENT The folding apparatus or mechanism 10 shown generally in FIG. 1 is commonly positioned at the discharge end of a collator (not shown) which collates a series of webs, such as paper and carbon transfer webs, to form a web assembly W. Preferably, the collator is provided with an output drive gear for driving the folding apparatus from a main drive 11, and the folding apparatus includes a frame consisting of parallel spaced vertical front and rear walls 12 and 13 and side plates or walls 14 and 15 (FIG. 2).

The assembled web W discharged from the collating machine is commonly provided with rows or lines of cross perforations 16 (FIGS. 8 and 9) which are spaced at regular intervals along the length of the web. The web is directed downwardly between vertical guide plates 17 and a set of endless feed belts 18 having outwardly projecting pins 19 which engage longitudinally spaced feed holes (not shown) within the margins of the web W. The feed belt 18 is driven by the main drive 11 and is effective to feed the web downwardly into a guide chute 20 having low friction internal plastic runners 21, preferably made of Celcon. Chute 20 is mounted for oscillation about a shaft 22 which is oscillated by a crank arm 23 driven by main drive 10. The rate of oscillation is correlated to the speed of the web W being fed into chute 20, and is commonly one complete oscillation for every two or four rows of cross perforations fed therethrough.

The folding mechanism includes folding head assemblies 2528 which are positioned in pairs on opposite sides of the oscillating chute 20. With reference to FIG. 3, folding heads 25 and 27 are joined and partially suspended for movement toward and away from one another by a shaft 31 running perpendicularly between front and rear walls 12 and 13, and heads 26 and 28 are similarly joined by a parallel shaft 32. Folding heads 25 and 26 are joined and partially suspended for movement toward and away from one another by a rail (not shown) and a drive shaft 37 mounted on walls 14 and 15, while heads 27 and 28 are similarly joined by a guide shaft 38 also mounted on walls 14 and 15. Heads 25 and 26 are connected by an elongated lead screw 41 which extends parallel to shaft 37 and is threaded in opposite directions for adjusting heads 25 and 26 perpendicularly to the laterally extending chute 20, while maintaining equal spacing between each head and the oscillating chute. A similar screw 42 connects heads 27 and 28, and together with screw 41 provides for producing folds of various lengths.

Shaft 37 is driven by main drive 11 for driving each of the folding head assemblies 25-28. Each of the cross shafts 31 and 32 is driven from shaft 37 by a set of hypoid gears 43 (FIG. 4), one gear of each set being keyed to an end portion of its respective shaft 31 or 32, and the other being keyed to shaft 37. Shafts 31 and 32, in turn, power heads 27 and 28, which are movable along shafts 31 and 32 for accommodating assembled webs of various widths. Movement of heads 27 and 28 on shafts 31 and 32 is controlled by lead screws 45 and 46 parallel thereto, which are threaded in corresponding support blocks 47 and 48. Blocks 47 and 48 carry the ends of shaft 38, on which heads 27 and 28 are mounted, for moving the heads with blocks 47 and 48. Lead screws 45 and 46 are interconnected for simultaneous movement, so that the folding heads 27 and 28 are movable as a unit for accommodating various web widths.

Folding heads 27 and 28 are substantially the same in construction, and include bevel gear sets 50 (FIG. 1) driving first vertical shafts 51 from respective power coupling shafts 31 and 32. Each vertical shaft 51 in each of heads 27 and 28 is coupled to a second vertical shaft 52 by a gear set 53. Each shaft 52 powers a gear belt drive 55 which passes across the bottom of each head 27 and 28 and connects to a toothed gear drive shaft 58 extending upwardly for driving corresponding folding spirals 60 .positioned below the guide chute 20.

Folding heads 25 and 26 are substantially alike and include the hypoid gears 43 (FIG. 4) mentioned earlier which drive shafts 31 and 32. An additional gear 62 is similarly driven from shaft 37 for driving a vertical shaft 64. Shaft 64 is connected at the bottom for driving a gear belt drive 66 (FIG. 2), which in turn drives another toothed gear drive shaft 58 which supports a folding spiral 60, just as with beads 27 and 28.

Vertical shafts 64 and heads 25 and 26 also include bevel gears 70 (FIG. 4) which drive respective beater shafts 72 and 73 passing between heads 25 and 27 (FIG. 3) and heads 26 and 28. The ends of shafts 72 and 73 opposite bevel gears 70 are supported for free rotation in folding heads 27 and 28 (FIG. 1). Each beater shaft mounts at least one, and commonly three or four beater members 80 mounted between the folding heads 25-28. Each beater member 80 includes a cylindrical hub 82 from which a wire formed semicircular beater element 84 projects. The beater members 80 are axially adjustable on their shafts 72 and 73 for accommodating various widths of assembled webs W.

As indicated, drive shafts 58 are toothed or splined (FIG. 7). The folding spirals 60 each have an upturned leading edge 86 on the top of the spiral which commences a double helical flight 87. The spirals also have open interior shafts 88 which are toothed to fit onto the toothed ends of shafts 58. Due to the fine spacing of the teeth on shafts 58 and on the insides of the spiral shafts 88, the spirals 60 may be precisely positioned on their respective shafts 58. When it is desired to change the phase of one of the spirals 60 with respect to the machine, such as by retarding or advancing the spiral slightly, it may simply be lifted off its corresponding shaft 58, turned slightly on its rotational axis (which is the same as that of its shaft 58) and replaced on the shaft in the new position. This provides for easy and accurate adjustment of each spiral without the need to alter the internal g'earing of the folding apparatus itself.

Each toothed portion of each shaft 58 extends above its coresponding folding spiral 60 to provide a toothed drive means adjacent the top of each spiral. Collars 90 having toothed interiors 91 are then adjustably received on the ends of the drive shafts 58 adjacent the tops of the spirals. Each collar 90 carries a folder arm 95 which, in the preferred embodiment, is a relatively stiff, flexible, resilient brush. When mounted on shafts 58, each of the brushes 95 projects in a generally radial direction substantially beyond the periphery of the spirals 60 adjacent thereto, and the positions of the brushes on the shafts 58 are similarly adjustable as those of the spirals 60, due to the toothed interiors 91 on the collars 90.

The collars 90, brushes 95, and spirals 60 are each retained on their respective shafts 58 by a lock washer 97 and a washer 98 all held by a manually operable thumb screw 99 threaded into the center of shaft 58 (FIG. 7).

The beater members 80, spirals 60, and chute are coordinated so that the toothed spiral gear drive shafts 58 make two revolutions and the beater shafts 72 and 73 each make one revolution for each oscillation of the guide chute 20. They are further coordinated so that beater elements 84 are rotated away from chute 20 as it swings over the folding spirals 60 nearest the corresponding beater elements 84. The movement of the web W through chute 20 is further coordinated so that the cross perforations 16 issue from the discharge end of the chute as the chute nears the extreme end of its oscillation closest to a beater shaft 72 or 73 (FIG. 9A).

As chute 20 begins its return oscillation back across the folding spiral and away from the beater members thereadjacent, the rapidly rotating spiral brings its leading edge 86 quickly into the fold which is forming along the cross perforations l6. Simultaneously, the beater elements 84 rotate around to strike the web and crease it along the cross perforations.

FIGS. 8A-8C and 9A-9C illustrate the formation of the crease as the web is zig-zag folded by folding apparatus 10.

In FIGS. 8A and 9A the chute 20 has just about reached the extreme end of its travel. There the movement of the chute has slowed and there is little except the momentum of the web itself to maintain a continuous feed of the web from the chute. At this point the folder arm portions enter the newly forming fold slightly ahead of the leading edge 86 of the spiral. Each folder arm brush 95 thus engages the web and pulls it firmly from the chute 20 to maintain proper feeding of the web and to keep the web bubble or loop under control. (In FIGS. 9A and 9B the brush 95 is shown figuratively as an arrow to emphasize the function of the brush at this time). Chute brushes 102 attached to the discharge end of the chute resiliently and smoothly guide the web W out of the chute and absorb any shocks during this transitional period.

FIGS. 8B and 9B illustrate the next step in the formation of the web, in which the function of the brushes 95 in pulling the web W from the chute 20 has been emphasized by slightly exaggerating the actual web overshoot caused by the brush. Just before the fold is formed on the cross perforations 16, the brush 95 will engage and urge the web loop a little bit outwardly beyond that line. Note that the web would be considerably retarded at this point with some prior art machines due to the slack which is caused during reversal of the chute movement.

The rapidly advancing leading edge 86 of a spiral 60 is clearly shown in FIGS. 8B and 8C. It engages the web at the cross perforations 16 (FIG. 8C) and restrains the web as the departing chute begins to draw the web taut. The operation is thus essentially a smooth and continuous one, preventing the web from being suddenly snapped taut as the spirals 60 engage the web during the return swing of the chute 20. In effect, the present invention pulls the web from the chute on the fore swing whereas in the prior art the web was pulled on the back swing, due to the relaxation in web delivery at the extremes of the chute travel.

The folder arms 95 also promote proper folding of the web at the cross perforations by engaging the web near the edges and behind the cross perforations, to prevent backfolding or separation of one or more unattached layers of the web at the web edge and to help break stiff glue lines where these exist. The brushes thus promote the formation of the desired crease along the perforations 16 and also assist in guiding the web folds into the spirals 60.

The flexible and resilient nature of the folder arm brushes 95 is particularly advantageous since the arms extend considerably beyond the peripheries of the spirals 60 themselves. As the spirals continue to rotate within the web folds (FIG. 8B) the flexible arm members are allowed to yield flexibly within the folds and to bend backwardly toward the peripheries of the folding spiral helical flights 87. In this way the folder arms 95 engage the web folds firmly to promote clean folding, yet yield to prevent tearing of the web during withdrawal of the arm members as the spirals continue to rotate.

As illustrated in particular in FIGS. 9A-9C, each single oscillation of the chute 20 lays down two layers of the web, and, as indicated earlier, the spirals turn two revolutions for each oscillation of the chute. Thus each spiral turns one complete revolution for each web layer, separating each layer by a spiral flight, as illustrated.

The web is thus supplied by feed belts 18 from a point of supply located upstream a distance from the region between and just beneath the folding spirals 60. The latter region serves as a stacking station since it is here that the web is zig-zag folded and stacked as it is swept back and forth just above the spirals and closely adjacent the stacking station.

As a result of the relationship between the oscillating chute 20, the folding spirals 60, the beater members 80, and the folder arms members 95, the portions of the assembled web W having the longitudinally spaced lines of cross perforation are fed directly into the folding spirals 60 from the lower end portion of the oscillating chute 20. This enables the web to be fed at a high rate of speed, with the folder arms 95 guiding the web onto the spirals and assuring that the web will be precisely folded on the lines of cross perforation, without any tears or jam ups. The web is fed continuously and smoothly from the chute at all times, avoiding extremes in the web tension. The resilient brushes 95 and 102 are durable, inexpensive, and uncomplicated. Further, the toothed gear drive shaft 58 and the matching toothed interiors 88 and 91 on the spirals and brush collars allow precise phase adjustments for every size and thickness of stock without the need for altering the internal drive connections of the machine 10.

While the method herein described, and the form of apparatus for carrying this material into effect, constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise method and form of apparatus, and that changes may be made in either without departing from the scope of the invention.

What is claimed is:

1. In apparatus for zig-zag folding a web of paper along lines of cross perforation between the web edges to produce a stack of partially connected folds, such as a series of business forms, and including means for feeding the web at a predetermined speed, spaced apart sets of folding spirals, the spirals having leading edges and being rotatably driven for folding the web on the lines of cross perforation, and an oscillatory guide member driven in timed relationship with the sets of spirals and the web feeding means for distributing the web back and forth between the folding spirals, the improvement comprising:

flexible resilient folder arms fixed relative to the spirals adjacent the leading edges thereof and projecting in a generally radial direction substantially beyond the periphery of the spirals to move simultaneously therewith to engage the web resiliently behind the cross perforations near the web edges to pull the web from the oscillatory guide member for continous feeding thereof and to promote folding of the web at the cross perforations while guiding the web to the spirals, said folder arms being sufficiently flexible to yield and flex backwardly toward the periphery of the spirals when engaging the web folds, to promote a clean fold and to prevent tearing of the web during withdrawal therefrom as the spirals continue to rotate.

2. The apparatus of claim 1 wherein said folder arms are resilient brushes.

3. The apparatus of claim 1 further comprising means releasably mounting said arms on the spirals adjacent the leading edges thereof.

4. The apparatus of claim 3 further comprising:

a. toothed gear drive means adjacent the top of each of the spirals,

b. collar means mounting each of said folder arms,

c. tooth means within each of said collars for drivably and adjustably attaching said collars to said toothed gear drive means adjacent each said spiral leading edge and independently of the positions of the spirals, and

d. means for securing said collars on said shafts adjacent the spirals.

5. The apparatus of claim 4 wherein:

a. said toothed gear drive means further comprises a toothed drive shaft for each said spiral and collar, and

b. each of the spirals further includes toothed means within each spiral for drivably and adjustably locating the spirals on said drive shafts independently of the positions of said collars.

6. The apparatus of claim 5 further comprising manually operable means for retaining each said spiral and collar on their respective said drive shafts.

7. In apparatus for zig-zag folding a web of paper along lines of cross perforation between the web edges to produce a stack of partially connected folds, such as a series of business forms, and including means for feeding the web at a predetermined speed, spaced apart sets of folding spirals, the spirals having leading edges and being rotatably driven in timed relation to the feeding means and arranged to engage the edges of the folding web near the lines of cross perforation, and an oscillatory guide member driven in timed relationship with the sets of spirals and the web feeding means, the guide member controlling the web as it approaches the spirals to distribute the web back and forth between the spirals, the improvement comprising:

stiff flexible arm members fixed relative to the spirals adjacent the leading edges thereof and extending radially outward therefrom substantially beyond the periphery of the spirals to move in timed relation therewith to engage the folding web at the cross perforations as the fold enters the spirals, said arm members pulling the web from the guide member and promoting folding of the web at the cross perforations, and said arm members being sufficiently flexible to yield and flex backwardly toward the periphery of the spirals when engaging the web folds, to promote a clean fold and to prevent tearing of the web during withdrawal therefrom as the spirals continue to rotate. i

8. The apparatus of claim 7 wherein said arm members further comprise elongated brushes adjustably attached to the spirals at the leading edges thereof to rotate therewith and project in a generally radial direction substantially beyond the periphery of the spirals, said brushes flexing yieldably within the web folds, backwardly toward the periphery of the spirals when engaging the web folds, to promote a clean fold and to prevent tearing of the web during withdrawal therefrom as the spirals continue to rotate.

9. ln apparatus for zig-zag folding a web of paper along lines of cross perforation between the web edges to produce a stack of partially connected folds, such as a series of business forms, and including means for feeding the web at a predetermined speed, spaced apart sets of folding spirals rotatably driven in timed relation to the feeding means and arranged to engage the edges of the folding web near the lines of cross perforation, and an oscillatory guide member driven in timed relationship with the sets of spirals and the web feeding means and controlling the web as it approaches the spirals to distribute the web back and forth between the spirals, the improvement comprising:

a. a toothed gear drive shaft for each spiral and extending above each top thereof, b, toothed means within each spiral for drivably and adjustably locating the spirals on said drive shafts, c. interiorly toothed collar means drivably and adjustably attachable to each of said portions of said toothed drive shafts extending aboveeach of the spirals, for location near the tops of the spirals,

d. means for adjustably securing said collars on said shafts in at least one fixed position relative to the spirals for rotation therewith, and

e. flexible, resilient brushes mounted on each of said collar means to rotate therewith and projecting in a generally radial direction substantially beyond the periphery of the spirals, said brushes flexing yieldably within the web folds, backwardly toward the periphery of the spirals when engaging the web folds, to promote a clean fold and to prevent tearing of the web during withdrawal therefrom as the spirals continue to rotate. 

1. In apparatus for zig-zag folding a web of paper along lines of cross perforation between the web edges to produce a stack of partially connected folds, such as a series of business forms, and including meaNs for feeding the web at a predetermined speed, spaced apart sets of folding spirals, the spirals having leading edges and being rotatably driven for folding the web on the lines of cross perforation, and an oscillatory guide member driven in timed relationship with the sets of spirals and the web feeding means for distributing the web back and forth between the folding spirals, the improvement comprising: flexible resilient folder arms fixed relative to the spirals adjacent the leading edges thereof and projecting in a generally radial direction substantially beyond the periphery of the spirals to move simultaneously therewith to engage the web resiliently behind the cross perforations near the web edges to pull the web from the oscillatory guide member for continous feeding thereof and to promote folding of the web at the cross perforations while guiding the web to the spirals, said folder arms being sufficiently flexible to yield and flex backwardly toward the periphery of the spirals when engaging the web folds, to promote a clean fold and to prevent tearing of the web during withdrawal therefrom as the spirals continue to rotate.
 2. The apparatus of claim 1 wherein said folder arms are resilient brushes.
 3. The apparatus of claim 1 further comprising means releasably mounting said arms on the spirals adjacent the leading edges thereof.
 4. The apparatus of claim 3 further comprising: a. toothed gear drive means adjacent the top of each of the spirals, b. collar means mounting each of said folder arms, c. tooth means within each of said collars for drivably and adjustably attaching said collars to said toothed gear drive means adjacent each said spiral leading edge and independently of the positions of the spirals, and d. means for securing said collars on said shafts adjacent the spirals.
 5. The apparatus of claim 4 wherein: a. said toothed gear drive means further comprises a toothed drive shaft for each said spiral and collar, and b. each of the spirals further includes toothed means within each spiral for drivably and adjustably locating the spirals on said drive shafts independently of the positions of said collars.
 6. The apparatus of claim 5 further comprising manually operable means for retaining each said spiral and collar on their respective said drive shafts.
 7. In apparatus for zig-zag folding a web of paper along lines of cross perforation between the web edges to produce a stack of partially connected folds, such as a series of business forms, and including means for feeding the web at a predetermined speed, spaced apart sets of folding spirals, the spirals having leading edges and being rotatably driven in timed relation to the feeding means and arranged to engage the edges of the folding web near the lines of cross perforation, and an oscillatory guide member driven in timed relationship with the sets of spirals and the web feeding means, the guide member controlling the web as it approaches the spirals to distribute the web back and forth between the spirals, the improvement comprising: stiff flexible arm members fixed relative to the spirals adjacent the leading edges thereof and extending radially outward therefrom substantially beyond the periphery of the spirals to move in timed relation therewith to engage the folding web at the cross perforations as the fold enters the spirals, said arm members pulling the web from the guide member and promoting folding of the web at the cross perforations, and said arm members being sufficiently flexible to yield and flex backwardly toward the periphery of the spirals when engaging the web folds, to promote a clean fold and to prevent tearing of the web during withdrawal therefrom as the spirals continue to rotate.
 8. The apparatus of claim 7 wherein said arm members further comprise elongated brushes adjustably attached to the spirals at the leading edges thereof to rotate therewith and project in a generally radial direction substantially beyond the periphery of the spirals, said brushes flexing yieldably within the web folds, backwardly toward the periphery of the spirals when engaging the web folds, to promote a clean fold and to prevent tearing of the web during withdrawal therefrom as the spirals continue to rotate.
 9. In apparatus for zig-zag folding a web of paper along lines of cross perforation between the web edges to produce a stack of partially connected folds, such as a series of business forms, and including means for feeding the web at a predetermined speed, spaced apart sets of folding spirals rotatably driven in timed relation to the feeding means and arranged to engage the edges of the folding web near the lines of cross perforation, and an oscillatory guide member driven in timed relationship with the sets of spirals and the web feeding means and controlling the web as it approaches the spirals to distribute the web back and forth between the spirals, the improvement comprising: a. a toothed gear drive shaft for each spiral and extending above each top thereof, b. toothed means within each spiral for drivably and adjustably locating the spirals on said drive shafts, c. interiorly toothed collar means drivably and adjustably attachable to each of said portions of said toothed drive shafts extending above each of the spirals, for location near the tops of the spirals, d. means for adjustably securing said collars on said shafts in at least one fixed position relative to the spirals for rotation therewith, and e. flexible, resilient brushes mounted on each of said collar means to rotate therewith and projecting in a generally radial direction substantially beyond the periphery of the spirals, said brushes flexing yieldably within the web folds, backwardly toward the periphery of the spirals when engaging the web folds, to promote a clean fold and to prevent tearing of the web during withdrawal therefrom as the spirals continue to rotate. 